Motor-vehicle suspension



Dec. M ,1923, AWA?? o. R. DUNNET MOTOR VEHICLE SUSPENSION Filed Sept. 6, 1921 Patented Dec. lil, IQZIq narran mirati @iE-WQ@ ORVILLE RANDOLPH DUNNET, OF CHARRA, `WEST COAST, SOUT AUSTRALIA, AUSTRALIA.

MOTOR-VEHICLE SUSPENSION.

Application filed September 6, 1921. ySerial No. 498,651.

To all whom t may concern:

Be it known that I, ORvrLLE RANDOLPH DUNNET, a subject of the King of Great Britain and Ireland, residing at Charra, I/Vest Coast, State of South Australia, Commonwealth of Australia, have invented certain new and useful Improvements in Motor-Vehiole Suspensions, 'of which the following is a specification.

My invention comprises an improved method of and means for mounting or at-` taching the half-elliptic springs usually employed in motor vehicle suspension.

Heretofore the half-elliptic spring (hereinafter called the main spring) has been tastened at its centre directly to the frame of the vehicle, the inner end of the spring being connected to the frame by a link and the outer end being attached to the axle or to the axle housing either through a link or directly, hence these springs are commonly known as cantilever springs. v

In vehicles employing the ordinary doublearmed or semi-elliptical springs the ends' of which are connected to the yvehicle frame, it has been proposed to employ a single-armed spring one end of which has been secured to the center of the semifelliptical spring, and the other end to the axle of the wheel.

According to my invention, instead of the rigid fastening to the vehicle trame,` I interpose between the frame and the main spring, a specially shaped supplementary quarterelliptic spring, the outer or butt end of which is rigidly fastened to the frame of the vehicle either directly or by means of a subframe or a suitable bracket and the inner end rests upon and is connected to the main spring at or near the centre thereof.

The object of my invention is to provide al spring suspension composed of a half-elliptic main spring and a quarter-elliptic supplementary spring so arranged or combined that, when the spring is subjected to severe strain or excessive weight, the main spring is stiifened by the movement outward towards the axle of its pointof contact with the supplementary spring, thereby reducing the etllective leverage of the axle over the spring, and thereby greatly reducing the possibility of the spring being strained by over-loading or when severe stress is put upon it. This permits of the use of a lighter spring adapted to carry the normal load and which, when thus automatically shortened, will have sufficient strength to take the abnormal strain or. heavier load.

This object I attain by attaching the outer or butt end of the quarter-elliptic supplementary spring to the vehicle frame approximately over the axle while its inner end rests upon the half-elliptic main spring at abouty the centre of same, such inner end being formed with a reverse curve so that the under face of the saidl supplementary spring forms an acute angle with the upper face ot the main spring. It will be apparent from the drawing that when abnormal strain or excessive load is applied and the springs are flattened the point of contact between the top tace of the main spring and the bottom face ot the supplementary spring moves outward toward the butt end of the supplementary spring and towards the axle, and so shortens the effective portion both of the main spring and of the supplementary spring.

In order that my invention and the man ner of its operation may be more readily understood andv carried into eilect I will describe the same with reference to the accompanving drawings in which- A Fig. l is a side view' showing the main spring and the supplementary spring.

Fig. 2vis a sectional view of the bracket 85 connection whereby the end of the supplementary spring is connected to the main spring.

Fig. 3l is a xperspective view of the bracket connection alone.

Fig. 4C is a diagrammatic plan of one type of iframe showing my invention applied thereto.

In the drawings 2 represents the main spring and 3 my supplementary spring.

The butt end of the supplementary spring, that at which the leaves are bolted or clamped together, is clamped or otherwise rigidly fastened to the frame of the vehicle and its yother end isconnectedl tov the main spring. 100

n Athe butt end ot my supplementary may be attached directly thereto,

or extension bars to take the butt end of thek supplementary spring.

The other end of the supplementary spring 3 rests upon and is connected to the convex back of the main spring Q, the connection being such as to permit ot a slight t of the leavesvertical movement oli' the endsof the spring 3 but preventing any endwise movement of those leaves uponV the main spring 2. y

The connection whichl show inthe drawings andv ,prefer comprises a bracket 5 rigidly fastened to main spring Q, and having ,two upwardly extending vertically slotted ears 6,y one upon each side oft the end of the springv 3,.in combination with a cross pin 7 carried inv an` eye formed in the end etI the. uppermost full length lealil ott the spring 3, the projecting ends of the cross pin 7 Aiitting, into the slots in the said ears @so that the-ends ot the leaves and the pin are capable of slight vertical movement but lare held against any endwise movement upon theback ot the main spring.V ,c IThe main spring 2. is arranged with its convex Jface uppermost and its two ends are connected as heretofore to the vehicle trame and to theA axle or to the axle housing respectively, in' some cases directly and in some cases by interposed links.

The upper shorter leaves of thel supplei' mentary spring 3 may have a simple downward curve only but the lower longer leaves have a second or reverse curve so that when ,thetwo springs are assembled and secured in position a V shaped space (with an acute the under face of back of the main angle); is formed ,between such leaves and the convex spring. f

The effect of this construction is that normally the Weight of the vehicle is applied throungh my supplementary spring 3 to approximately the centre of the main spring 2v and so to the axle, but when an excessive load is applied or whena severe rise ofthe wheel the springs are deflected and the point of contact (which is the point of support) between the back of the ymain spring 2 and the 'face ot the supplementary spring -moves outward towardsthe but-t endv of supplementary spring and the axle shortening the effective length ot both springs. and thereby, s tiil'ening the spring and shortening the relative leverage of the axle. l

n- Fig. l

. lvahicle frame@ to which a subframe has been attached for the purpose of aflixing my invention.v n Such subtrame comprises four-'rdiverging bars Vl0 fastened to the 'original the combination with a ythe point of outer end being connected is shown diagrammatically al 'thereof and having spaced ears provided 130 oli the axle or ot the axle housing to the frame of the vehicle it will be necessary to providesuclirods to keep the axle in alignment. l

What l' claim is:

1. In a motor vehicle spring suspension half-elliptic main spring arranged with its convex tace uppermost' its outer and inner ends being connected to the axle and to the frame respectively, ot a specially shaped quarter elliptic supplementary spring rigidly fastened at its outer and butt end to the vehicle frame approximately over the axle and having its inner and free end resting directly upon vthe main spring approximately at' the vcentre thereof such free end having a reverse curve whereby when severe strain is placed upon the springs and the springs are ii'attened contact between the springs moves nearer tothe butt end ot the supplementary spring and vto the axle.

2. A motor vehicle spring, suspensioncomprising 1-a half-elliptic main spring arranged with its convex face uppermost,its

to the axle and its inner end tothe vehicle frame; a quarterelliptic supplementary spring arranged vertically above the main spring and with its convex face uppermost, its outer and butt end being rigidly fastened to' the vehicle frame approximately overv the axle and its inner and free end beingsupported by the main spring at about the centre thereof, its tree end being reversely curvedv and resting directly upon the back olf' the main spring approximately at the center thereof and forming anacute angle therewith, whereby when a severe strain is placed upon the springs and the springs are flattenedI the point of' contact between the springs moves nearer'to the butt end ot the supplementary ,springv and to the axle; and means tor connecting the freeend of the supplementary spring to the main spring said means permitting vertical movement and preventing endwise movement of the end of the supplementary spring relatively to the main spring.

3. A comprising a halt-elliptical main spring arranged with its convex (face uppermost and, having itsends connected to the axle bracket secured to the motor vehiclev spring suspension.

with vertical slots7 and a quarter-elliptical supplementary spring having its butt end secured to the vehicle frame, the other end of the said spring being reversely curved and resting directly upon the main spring between the ears of the bracket, said end being provided with a transverse pinextending into the slots of said ears.

In testimony that I claim the foregoing as my' invention I have signed my name in 10 the presence of tivo subscribing Witnesses this 21st day of July, 1921.

ORVLLE RANDULPH DUNNET. Witnesses:

ARTHUR GORE COLLISON, KATHLEEN MARY CoLLIsoN. 

